Power regulation



1 E. FRIEDLANDER ET AL 3 POWER REGULATION Filed Sept. 3, 1938 3Sheets-Sheet 1 A 7 I r; /3 27 8 9 x -1 179x PM ("W AE'O j r E WITNESSES:V INVENTORS Eric/7 Fried/nder 1939. E. FRIEDLKNDER ET AL 2181,3

POWER REGULATION Filed Sept. 3, 1938 1. Sheets-Sheet 2 INVENTORS Eric/7Fried/fir! def WITNESSES:

E. FRIEDLANDER ET AL 2,181,321

POWER REGULATION No v. 28, 1939.

Filed Sept. s, 1938 is Sheets-Shet 5 INVENTORS WITNESSES:

Patented Nov. 28, 19 39 UNITED STATES PATENT OFFICE POWER REGULATIONration of Pennsylvania 3, 1938, Serial No. 228,336 August 19, 1937Application September In Germany 10 Claims. (01. 171-119) lated circuit,resulting in a zero power output- Our invention relates to powerregulating equipment such as may be employed for controllllllls thepower flow in alternating current circ order to govern the flow of powerin alternating current electric. circuits, it has been proposed todevelop voltage components corresponding vectorially to the sum and tothe difference of two voltages that are proportional, respectively, tothe voltage 'and to the current of the circuit being regulated, and tocompare the magnitudes of the vector sum and the vector diflerence ofthese two values after rectifying them separately to unidirectionalquantities. If the vector-representing the voltage of a circuit is verylarge in comparison with the vector representing current in thatcircuit, the difference of the voltage proportional vector and currentproportional vectors becomes substantially proportional to the currenttimes the power factor. This quantity is, however, proportional to theactual power flow only when the voltage of the circuit is constant. Tomeasure the power of the circuit independently of the constancy of thevoltage, it has been proposed to develop a vector in quadrature with thevoltage vector by inserting reactors having saturated core structures inthe conductors supplying the rectifiers. Thus the difierences in therectified voltages may be made proportional to the measured power. This,however, requires reactors which must be balanced in a special manner.Since, also, the two rectifier units are not equally loaded, rectifiedharmonics appear which give rise to undesirable disturbances.

This invention avoids these difliculties. In accordance with theinvention, regulating apparatus is provided for effecting the summationof vector components including a phantom or local circuit into which isintroduced a voltage vector that is a measure of the current flowing inthe power circuit to be regulated, and a vector that is a measure of thevoltage of the circuit being legulated. An auxiliary current'componentvector or voltage component vector is also introdnced into the phantom,circuit which, when added and subtracted vectorially together with theinitial components of the circuit, establishes th basis for a measure ofthe desired value 01 and vector difference of these vectors are sup- 4plied to a zero bridge circuit and separately rectifrom the bridgecircuit. If the power in the regulated circuit varies from this chosenvalue, a large difierential current in the one or the other directionflows from the unidirectional output of,

the bridge circuit which 'may be used for regulating purposes.

The regulating apparatus that is energized from the phantom circuit andthat supplies current to the zero power bridge circuit is thus employedas a device that depends for its operating characteristics upon thevariation at the phase angle between the regulating current and siredfrom the regulated circuit. The'vector introduced into the circuit ofthe apparatus that is derived from the voltage of the power circuitthrough mechanism which varies the magnitudeof the current in suchmanner that it decreases for rising circuit voltage, so that the powerformed from this current and the combined voltage is alwayssubstantially constant. This value corresponds to the desired value ofthe power in the regulated circuit. Also, equipment may be used in whichthe phase rotation in non-linear systems are employed, such, forexample, as a choke coil with parallel impedance which may be excited bythe current of one of the phase conductors of the power circuit, thevoltage across this choke being inserted as an auxiliary potential inthe potential-path of the power regulator. It is advantageous tosci-connect these devices which supply auxiliary current or auxiliaryvoltage in' the voltage circuit, or in the current circuit,respectively, that they are not influenced by the current or voltagetransformers that supply the current or the voltage to the reg-- uiatingapparatus.

In the drawings:

Figure 1 is a diagrammatic view of circuits and apparatus for developinga control potential in accordance with our invention; 1

Fig. 2 is a vector diagram illustrating the vec tor quantities in theseveral parts of the circuits of Fig. i; I

Fig. 3 ice diaatic view illustrating a gfionsgant power device that maybe employed in Figs. 4 and 5 are curves illustrating the operation ofthe equipment shown in Fig. 1;

Fig. 6 is a diagrammatic view of circuits and apparatus employinganother embodiment of the invention;

Fig. 7 is a diagrammatic view of circuits and apparatus illustrating thedevelopment of vector quantities for use as a power comparison unit inanother embodiment of the invention;

Figs. 8 and 9 are diagrammatic illustrations of curves and vectorquantities explaining the operation of the mechanism as disclosed inFig. 7;

Figs. 10 and 11 illustrate apparatus that may 'be employed to neutralizeundesirable effects of variable loading of the bridge circuit employed;and

Fig. 12 is a diagrammatic view of apparatus and circuits illustrating acomplete power regulating system organized in accordance with theinvention.

Referring to Figure l, the numerals-i and 2 identify two full waverectifier units, each unit comprising four rectifier elements connectedin a well known manner. An alternating voltage that is the vector sum ofthe potential E and a current proportional vector In is supplied to oneof the rectifier units. The other rectifier unit is supplied with analternating voltage that is the vector difierence of the vectors E andInX. A voltage transformer 3 is provided having a primary winding 5connected to conductors 5 and 6 of the three-phase power circuit 5, 6and l to be regulated, and having two secondary windings 3 and 9. Acurrent transformer ii is also provided, the primary winding of which issupplied with current from the three-phase conductor l, and thesecondary winding of which is connected through conductors i2 and it tothe primary windings of choke coils or transformers it and H5. Thesecondary winding of the transformer BS feeds the rectifier unit 0through a circuit including the secondary winding 8 of the voltagetransformer 3 and conductors 116 and ill. The

, secondary winding of the transformer is feeds the rectifier unit 2 inseries with the secondary winding 9 of the voltage transformer 8.

In Fig. 2 the vector diagram of the voltage components developed in thisphantom circuit is illustrated. The vector E is proportional to thepower-circuit voltage and represents the voltages developed in thesecondary windings ii and ti oi the potential transformer 3. Thequantity in)? is a vector that is proportional to the power cir== cuitcurrent and represents the voltage impressed across the primary windingsof the choke coils or transformers id and it, as a result of the currenti In flowing from the secondary winding of the current transformer ii.The rectifier units 6 and 2 are connected together at the point 2i andimpedance devices 222 and 23 are connected re spectively in the outputcircuits therefrom, an impedance 25 being connected between the junctionpoints 24% and 29 as illustrated.

When the output voltages of the rectifier units l and 2 are alike, thepotential of the point it corresponds with that of the point 28, so thatno current flows through the impedance 25. en the potential outputs fromtherectifiers l and 2 are unequal, current will flow through theinnpedance in the one or in the other direction depending upon whichoutput voltage is larger and the value of the diderential voltages.Since arouses.

it is the real power that it is desired to regulate, and since thevoltage on the choke coils l4 and i5 are displaced in phase withreference to the current by 90, 9, potential E is selected as shown inFig. 1 that is displaced by 90 in phase with reference to the currentfrom the transformer l l. The introduction of the vector sum and vectordifference of the initial voltage and current pro portional vectors intothe phantom circuit will therefore supply a differential current throughthe impedance 25 that is substantially proportional to the current inthe regulated circuit times the power factor of the circuit if thepotential is chosen sufliciently high.

According to the invention, the introduction of an auxiliary voltagecomponent into the phantom circuit may be used to develop a currentoutput thatmay serve as a standard of comparison of actual power todesired power in the regulated circuit. This current appearing in theimpedance device 25 becomes zero when the regulated power becomes thedesired value, and varies in polarity and magnitude as the power in theregulated circuit varies from the desired value in the one or in theother direction. For this purpose an auxiliary current may be derived,for example, from the potential E through a constant power device 26which current, together with the potential E, develops a measure of thedesired constant power.

The primary conductors 21 and 28 of the constant power device 26 areconnected to the conductors supplying the voltage transformer 3, and thesecondary conductors 29 and 3| from the device 26 are connected toalsosupply current to the primary windings of the choke coils ortransformers H and 5.5. It will be seen, therefore, that the vector sumof the two currents is applied to the primary windings of the chokecoils i4 and 85. One of these currents In is derived from the currenttransformer ii and is proportional to the power circuit current. Theother of these two currents In is derived from the constant power device26 that is connected to the other two phase conductors from the currenttransformer ll.

The current supplied to the choke coils I4 and it may be purely wattlesscurrent for the desired value of power to be regulated; In this mannerthe simple zero power bridge connection becomes accurate even withoutthe supply of quadrature current thereto and operates to develop acurrent that varies upon variation of the regulated power from thedesired value.

-Reierring to Fig. 2, the auxiliary potential vector produced by theauxiliary current hfrom the constant power device it isplotted andidentified by llnX. It is seen that for the proper angle between IRX andE varies from 90 and 7 produces a difierence in the vectors E1 and E2for developing different output voltages from the rectifier units [I andi2 and a differential current.

A constant power device which satisfies the above mentioned requirementsis'illustrated in 3.- It consists of two choke coils 32 and 33, one ofwhich is saturated and the other unsaturated. The primary windings areconnected in series through conductors 21 and 24 and energized inaccordance with the voltage between power circuit conductors I and 4.The secondary windings are connected in series opposition to each otherand to conductors 23 and 3|. If the voltage across each choke coil isplotted as a function of the current therethrough as illustrated in Fig.4, then a region exists between the two characteristic voltage currentcurves in which the difference in voltage AEo for light current valuesis hyperbolically dependent on the current. In corresponding manner asimilar hyperbolical characteristic line of the short circuit currentAIK with varying potential may be shown.

In Fig. 5 the curve illustrates the relationship existing between thedifferential current and voltage or the differential voltage andcurrent. It will, therefore, be seen that with the proper displacementbetween these currents and potential values a constant power may beexpressed by combining the difference current with the voltage or bycombining the difference voltage with the current through the chokecoils which appears nowhere, as electrical power but which establishes avalue that may be used as a unit for measuring a desired value of power.

In Fig. 6 a constant power regulator is illustrated having a constantpower device equivalent to that above described. To the extent that theparts correspond with those illustrated in Fig. 1 the same referencenumerals are applied. The primary windings of the voltage transformers34 and 35 are excited from one phase of the threephase potentialtransformer 36, the circuit including an auxiliary transformer 31, theprimary winding of which is connected to the other two phase windings ofthe transformer 35 to compensate for the loss in the phase angleoccasioned by the choke coils l4 and IS. The primary winding of thesechoke coils are excited by two components of current, one of which, In,is the vector difference of two phase current which are derived from thecurrent transformers H and H. The second or auxiliary current componentis derived from a constant power device which consists of an unsaturatedchoke coil 33 and a saturated choke coil 39. These choke coils areconnected in series between a potential divider 4| to the power circuitconductors 5 and 5, so that the current In supplied therefrom has theproper phase relation to the potential vector E. The constant powerdevice differs from the structure shown in Fig. 3 in that the choke coil33 having an air gap is tapped and the saturated choke coil has nosecondary winding.

.An unsaturated choke coil 42 is connected in series with the saturatedchoke coil 35 for adjusting the slope of the saturating curve. Inaddition, a condenser 43 and a choke coil 44 are connected in parallelto the series circuit of the saturated choke coil 39 and the unsaturatedchoke coil 42 to suppress harmonics. By employing the circuitsillustrated in Fig. 6, small power variations in the regulated currentproduces a larger usable differential current AI even when the powerfactor is poor. The two rectifiers are equally loaded at the desiredvalue of power, so that inequalities which arise from harmonics areeliminated.

While certain constant power devices have established only the phaseposition of the auxiliary current vector with reference to the voltagevector, it is also possible to develop the measure of a constant powerbyemploying phase relations that occur in non-linear systems ofsaturated choke coils and impedances. The operation of such a constantpower device may be explained by reference to Figs. 7 and 8. In Fig. 7 asaturated choke coil 45 is connected in parallel with an ohmic resistor46 that is connected in series with the power circuit conductor 6. Thevector sum of the currents in the elements 45 and 46 is equal to thephase current Is of the three-phase system and may be used fordeveloping a quantity indicating constant power if it is brought intothe proper relationship with a potential that is displaced by an angle 9with reference to the potential on the saturated choke coil 45 andproport-tonal to it. The angle 0 must be selected somewhat greater thanthe inclination angleof the characteristic curve of the choke coil 45 inthe saturated range because the auxiliary voltage rises somewhat withthe choke coil potential En.

' In Fig. 8 the relationships are illustrated for' two different valuesof current Is. The angle 9 Conversely, the voltages on the choke coil45,.

when combined with a current displaced by an angle 9 with reference tothe phase current Is,

must be so selected that the product of the voltdevelops a quantity thatis representative of a it. Conversely, also the phase current Is may beused and the choke coil 45 excited from two other currents in suchmanner that the desired current between Is and the choke potential ispresent.

In Fig. 9 the vector diagram illustrates the component vectors fromwhich the sum and difference voltage values shown dotted) are developed.To the potential vector IsX, potential vectors E1. and EH are added andsubtracted vectorially and the two resulting voltages, sepa-, ratelyapplied to the two rectifier units so thatfor a predetermined real valueof power in the regulated circuit the difference of potentials developedin the bridge is equal to zero.

The current In derived from the constant power device always operateswith the variable power circuit current In on the zero power bridgecircuit of the two rectifier units. Consequently the constant powerdevice is not uniformly loaded. To neutralize harmful reactions ofvariable loading, it is preferable to supply to the constant powerdevice a power circuit current component in the opposite sense. Anembodiment of apparatus for doing this is shown in Fig. 10. The device53 in Fig. 10 is the regulating apparatus for supplying the zero powerbridge and whichmay correspond, for example, to the-apparatus enclosedwithin the dotted line 53 in Fig. 6. The regulating apparatus issupplied with a voltage component from the potential transformer 54 thatcorresponds to the voltage of the power circuit. A vector componentcorresponding to current In is also supplied to the apparatus from thecurrent transformer 55. The current transformer is i1- lustrated astapped at the center, and its two outer terminals are connected throughthe regulating apparatus 53 and through an impedance device 56 that areconnected in series. The impedance 5515 so dimensioned as to correspondtov Consequently, the loading of the constant power 5 device 26 isindependent of the magnitude of the current supplied by the transformer55. In the arrangement illustrated in Fig. 10 the quantity used as astandard of comparison for the regu lated power was derived from thepotential and introduced into the current transformer circuit, while inthe arrangement illustrated in Fig; 11

the comparison power component is derived from the current transformerand introduced into the potential transformer circuit. The constantpower device is again identified by the numeral 26 and is excited fromthe current transformer 50 which also supplies the component In to theregulating apparatus 53.

The potential transformer 56 is provided with a secondary winding-whichfeeds the series circuit including the impedance 6! and the apparatus53. The impedance 6I is so dimensioned that it is equal to the impedanceof the regulating apparatus 53 in the potential circuit, and thereforeequal to the impedance which opposes the flow of current through thepotential transformers in the apparatus 53. The constant power device 26that supplies the auxiliary potential is connected between the centerpoint 62 of the potential transformer 59 and the point 63 between theapparatus 53 and the equivalent impedance GI, so that it is notinfluenced by the power circuit potential.

In Fig. 12 a complete power regulating system :for maintaining the poweroutput of a generator is illustrated. I The power regulating equipmentis shown in the portion of the diagram enclosed within dash lines. Inthe figure a propeller driving motor I09 is illustrated that is excitedby a generator IIO, the field windinglof which is supplied with currentfrom a constant direct current source such as conductors M6. The motorI09 is supplied with energy through three phase circuit conductors 5,6and I from an alternating current generator H2 that is driven bya primemover, such as a, Diesel engine I I I. The generator II2 may be excitedfrom a generator I06,

having a field winding I0? that is energized in part from the constantpotential source I08, and in part froma generator I03. The generator I03is connected in parallel with a resistor I05 and provided with a fieldwinding 104 that is connected to be energized in part from the constantpotential source I06 and in part from the pilot generator I00. The pilotgenerator I00 is provided with a shunt field winding I02 and a fieldwinding IOI that is connected by conductors 615 and 64 to junctionpoints 24 and 2i, respectively, corresponding to the impedance device 25in the circuit in Figs. 1' and 6.

Two full-wave rectifier units I and 2. supply unidirectional current tothe impedance devices 22 and 23 in the same manner as explained withrelation to Figs. 1 and 6. A potential transformer I47 and the severalsecondary windings I48, I 49.

I50 and I5I. The device I54 is an unsaturated choke coil having an airgap and provided with primary windings I55 and I56 and with a, sect:iriary winding I51. A second non=saturating choke coil I60 is providedhaving an air gap and provided with primary windings 16E and i6? andwith a secondary winding I66. I

The saturated choke coil is excited from two current transformers I61and I68 that are connected respectively in phase circuit conductors 6and I. As illustrated, the unsaturated coils I54 and I60 are alsoenergized from the same current transformers. The number of turns are soselected that the potential impressed on the secondary windings I48 andI49 of the saturated choke coil I45 are at an angle with respect to thevoitages impressed on the choke coils I56 or Md and proportional to thecurrent, and having a magnitude such that the indicated power resuitingfrom combining these two vectors is constant when the current flowingthrough the current transformers I61 and I68 v aries'and that for thedesired value of power the two potentials acting on the rectifier areequal. The proper angular relationship between the vector values to beselected appears by reference to Fig. 8 and the description relatingthereto. The rectifier unit I is supplied with the sum of the voltagesdeveloped in the windings I42, I48 and I5! (ErI-En-I-IsX). The rectifierunit 2 is supplied with the sum of the potentials developed in .windingsI45, I40 and the counter potential of the winding I63 (En|-EHISX) Thiscorresponds substantially to the values represented vectorially in Fig.9 with the difference that for the formation of the potential affectingthe second rectifier unit E+EnlsX represents a vector in which the lastof the three named vector components is in a reverse direction from thatshown in Fig. 9. The resultant sum of the three voltage components,however, corresponds in magnitude to the potential and the resistor I53which corresponds to the impedance that opposes the fiow of current thetransformer I40 are connected in the circuit.

Only the imposed potential and the absorbed current of the transformerneed therefore be measured. Accordingly the same arrangement asillustrated in Fig. 11 is employed. To relieve the saturated choke coilI45 from too high wattless currents which arise from the fact that thechoke coils I 54 and I60 are present, a condenser I10 is connected inparallel to the secondary winding I5I. The ohmic resistorshown as 46 inFig. 'I' is here absent, it being replaced by the loading produced bythe rectifier with its impedance and the choke coils I54 and I80 becauseit is apparent that foran arrangement according to Fig. '7 the impedance46 need not be a purely ohmic resistance. I

The differential current acting on the field winding II of the pilotexciter I00 varies the voltage output of that machine to control thevoltage output of machines I03 and I06 and, therefore, of the generatorH2 in a well known manner. erator H2 is regulated by controlling itsexcitation. As the output of the generator varies from the chosen valuea positive or a negative unidirectional current is supplied in the oneor the other direction through the field winding Illl to limit or tocorrect for variations in the power through 1. In a regulating systemfor governing the power flow in a regulated alternating current circuit,a phantom circuit including a circuit part in which a component isdeveloped that corre-' sponds to the current of the regulated circuit, acircuit part in which a component is developed that corresponds to thevoltage of the regulated circuit, a constant power device for developingan auxiliary voltage component of such value and phase relation thatwhen combined with one of said first two named components develops amodified component that is in quadrature with the other of said firsttwo named components for a chosen power fiow through the regulatedcircuit, an impedance network including induction apparatus fordeveloping the vector sum and the vector difference of said current andvoltage components, rectifier means for developing a resultantunidirectional voltage that corresponds to the difference in magnitudeof the vector sum and the vector difference components, and meanscontrolled by said unidirectional voltage for regulating the power insaid regulated circuit.

2. In a regulating system for governing the power flow in a regulatedalternating current circuit, a'phantom circuit including a circuit partin which a voltage component is developed that corresponds to thecurrent of the regulated 4:51- cuit, a circuit part in which a voltagecomponent is developed that corresponds to the voltage of the regulatedcircuit, means for developing an auxiliary voltage component of suchvalue and phase relation that when combined with one of 'said first twonamed components develops a modified component that is in quadraturewith the other of said first two named components for a chosen powerfiow through the regulated circuit, means for developing the vector sumand the vector difference of said current and voltage components, meansf or separately rectifying the vector sum and the vector difference ofsaid current and voltage vectors, and means controlled by the differencein magnitude and polarity of the rectified voltages for controlling thepower in said regulated circuit.

3. In a regulating system for' governing the power flow in a regulatedalternating current circuit, means including a transformer fordeveloping a voltage component that is proportional to the current ofthe regulated circuit and transformer means for developing a voltagecomponent proportional to the voltage of the regulated circuit meansincluding induction apparatus for developing two voltages corresponding,respectively, to the vector sum and the vector difference of the currentand voltage proportional components, means for developing an auxiliaryvoltage component of such value and phase relation with respectto one ofsaid first two components that Thus the power delivered by the genthemodified component which results is a measure of the desired power to beregulated.

'4. In a regulating system for governing the power flow in analternating current circuit, a

circuit network including means for developing a voltage componentproportional to the current 'of the regulated circuit, and a voltagecomponent proportional to the voltage of the regulated cirponents fordeveloping two voltages corresponding, respectively, to the vector sumand the vector difierence of the current and voltage proportionalcomponents, and means for developing an auxiliary voltage component ofsuch value and phase relation with respect to one of said first twocomponents that the modified component cuit, and means for combiningsaid two comwhich results is a measure of the desired power to beregulated, said means comprising a constant power device for developingan auxiliary component having the characteristic that the power formedbythe supplied voltage and the delivered current is substantially constantfor varying supplied voltages.

5. In a regulating system for governing the power fiow in an alternatingcurrent circuit, a circuit network including means for developing avoltage component that is proportional to the current of the regulatedcircuit and means for developing a voltagecomponent that is proportionalto the voltage of the regulated circuit, and two circuits includinginductive apparatus for combining said two components for developing twovoltages corresponding, respectively, to the vector sum and the vectordifference of the current and voltage proportional components, and meansfor developing an auxiliary current component comprising a constantpower device connected to be energized in accordance with the powercircuit voltage for so varying the current delivered therefrom that thepower formed by the auxiliary current component and the voltagecomponent is constant.

6. In a regulating system for governing the power flow in an alternatingcurrent circuit, a

circuit network including means for developing a voltage component thatis proportional to the current of the regulated circuit and a voltagecomponent that is proportional to the voltage of the regulated circuit,and means for. combining said two components for developing two voltagescorresponding, respectively, to the vector sum and the vector diflerenceof the current and voltag proportional components, and means fordeveloping an auxiliary voltage component comprising adevice connectedto be energized in accordance with the power circuit current at such aphase angle that the power formed by the auxiliary voltage component andthe current component is a constant.

7. In a regulating system for governing the power fiow in an alternatingcurrent circuit, a circuit network including means for developing avoltage component that is proportiona to the current of the regulatedcircuit and a voltage component that is proportionalto the voltage ofthe regulated circuit, and means for combining said two-components fordeveloping two voltagw corresponding, respectively, to .the vector sumand the vector diflerence of the current and voltage proportionalcomponents, and means cuit voltage for so varying the current deliveredtherefrom that the power formed'by the auxiliary current component andthe voltage com circuit, a circuit network including means fordeveloping a voltage component proportional to the current of theregulated circuit and a voltage component proportional to the voltage ofthe regulated circuit, and means for combining said two components fordeveloping two voltages corresponding,"respectively, to the vector sumand the vector difference of the current and voltage proportionalcomponents, and means for developing an auxiliary voltage componentcomprising a device connected to be energized in accordance with thepower circuit current at such a phase angle .that the power formed bythe auxiliary voltag component and the current component is a constant,said device including a saturated choke coil in series with a powercircuit conductor and an impedance in parallel therewith.

9. In a regulating system for governing the power flow in a regulatedalternating current circuit, regulating apparatus for developingvoltages corresponding, respectively, to the vector sum and to thevector difierence of current and voltage components derived from theregulated circuit, a local circuit for supplying said regulator having acircuit part including a current transformer for supplying a currentcomponent to the regulator that is a measure of the current in theregulated circuit, a circuit part including a voltage transformer forsupplying a voltage component to the regulating apparatus thatis ameasure oi the voltage of the regulated circuit, and

a circuit part including a device for developing an auxiliary vector ofsuch'magnitude and phase relation with respect to the current dependentvector or the voltage dependent vector as to 1 give a powercorresponding substantially to the greases desired value of the power tobe regulated, characterized by the fact that the transformer supplyingthe current for the regulator is tapped at the center and that the twoends of the current transformer winding are connected to supply acircuit including in series the regulator and an impedance device havingan impedance corresponding to the impedance of the regulator, and thatthe device for developing the auxiliary vector component is connectedbetween the impedance device and the regulator.

10. In a regulating system for governing the power flow in a regulatedalternating current circuit, regulating apparatus for developingvoltages corresponding, respectively, to the vector sum and to thevector difference of current and voltage components derived from theregulated circuit, a local circuit for supplying said regulator having acircuit part including a current transformer for supplying a currentcomponent to the regulating apparatus that is a measure of the currentin the regulatedcircuit, a circuit part including a voltage transformerfor supplying a voltage componentto the regulating apparatus that is ameasure of the voltage of the regulated circuit, and a circuit partincluding a device for developing an auxiliary vector of 1 suchmagnitude and phase relation with respect to the current dependentvector or the voltage dependent vector as to give a power correspondingsubstantially to the desired value of the power to be regulated,characterized by the fact that the voltage transformer'supplying thevoltage to the regulating apparatus is tapped at the center and the twoends are connected to a circuit including the regulating apparatus andan impedance device connected in series, said impedance device having animpedance equal to the impedance of the regulator, and that the devicewhich supplies the auxiliary component to the apparatus is connectedbetween the center point of the voltage transformer and a junction pointbetween the impedance device and the regulating apparatus.

OSKAR SC.

